Avicenna’s logical theory of negative judgement can be seen as a systematic development of the insights Aristotle had laid out in the De interpretatione. However, in order to grasp the full extent of his theory one must extend the examination from the logical works to the metaphysical and psychological bases of negative judgement. Avicenna himself often refrains from the explicit treatment of the connections between logic and metaphysics or psychology, or treats them in a rather oblique fashion. Time and again (...) he is satisfied with noting that this or that question is not proper for a logician and should be dealt with in metaphysics or psychology—without bothering to refer his reader to the exact loci. The following is an attempt at a reconstruction of Avicenna’s theory of negative judgement in such a broad fashion. I will begin with his analysis of negative judgement as resulting from an operation of ‘removing’ the predicate term from the subject term. On this basis, I will move on to discuss how he conceives of the relation between negative judgements and affirmative judgements that contain privative or metathetic terms as well as the question of whether negative judgements can be reduced to affirmative ones. Having thus laid out his logical theory of negation, I move on to discuss the underlying metaphysics by looking at the relation between existence and non-existence, and existence and privation. Finally, I will address Avicenna’s scattered psychological remarks on how we can conceive of what does not exist. (shrink)